Multi-fuel turbine combustor, multi-fuel turbine comprising such a combustor and corresponding method

ABSTRACT

Combustor ( 50 ) for use in a turbine ( 100 ). The combustor ( 50 ) comprising a multiple fuel atomizers ( 10 ) which has a gas inlet for feeding gaseous fuel as first combustible into an inlet zone of the atomizer, an air inlet for feeding compressed air into the inlet zone, and an orifice for injecting a liquid fuel as second combustible into the inlet zone. The atomizer comprises a diffuser for emitting a gas stream at an exit side. The atomizer ( 10 ) is arranged with respect to a combustion chamber of the combustor ( 50 ) so that the exit side of the diffuser points in a tangential direction relative to the combustion chamber. The combustor ( 50 ) comprises an outlet duct ( 51 ) for discharging an exhaust gas produced by a combustion process of the gas stream inside the combustion chamber. The exhaust gas drives a turbine ( 63 ).

CROSS-REFERENCE TO RELATED APPLICATION

This application is entitled to the benefit of and incorporates byreference subject matter disclosed in International Patent ApplicationNo. PCT/EP2012/066106 filed on Aug. 17, 2012.

TECHNICAL FIELD

The present invention relates to multi fuel gas turbine combustors andmulti-fuel turbines comprising such a combustors. The present inventionalso relates to a method of combustion within a reverse flow annularcombustor.

BACKGROUND OF THE INVENTION

A number of technologies are emerging which are designed in order toefficiently generate electricity. Some of them are combustion basedsystems where a combustible fluid (herein referred to as fuel) isoxidized.

There is a particular need for gas turbines which are designed tocombust gas.

SUMMARY OF THE INVENTION

The objective of the present invention is thus to find a combustorlayout and a multi-fuel gas turbine set-up which can be switched betweenat least two different combustible fuels, one in liquid and one ingaseous form.

According to the invention, a combustor for use in a turbine isprovided. The combustor comprises multiple fuel air blast atomizerswhich can be operated at least on a liquid fuel and on a gaseous fuel.Each air blast atomizer comprises a gas inlet for feeding a gaseous fuelas first combustible into an inlet zone of the air blast atomizer, anair inlet for feeding compressed air into the inlet zone, and an orificefor injecting the liquid fuel as second combustible into the inlet zoneor into an area close to the inlet zone. The air blast atomizer furthercomprises a diffuser for emitting a gas stream at an exit side into aprimary combustor zone of a combustion chamber. This gas streamcomprises the gaseous fuel, the compressed air and the liquid fuel. Thecombustor comprises a combustion chamber. The air blast atomizer isarranged with respect to the combustion chamber of the combustor so thatthe exit side of the diffuser points in a tangential direction relativeto the combustion chamber to create a main vortex flow. The combustorfurther comprises an outlet duct for discharging an exhaust gas producedby a combustion process of the gas stream inside said combustionchamber.

An air blast atomizer for the purposes of the present invention is usingkinetic energy of air to atomize liquid fuel and to decrease the timewhich is needed for the vaporization.

Preferrably, the air blast atomizer is arranged with respect to thecombustion chamber of the combustor so that the gas stream istangentially discharged via the exit side of said diffuser into thecombustion chamber where due to this form of directed discharging avortex is established and maintained.

According to the invention, a multi-fuel gas turbine is provided as afuel-burning device which is designed to burn multiple types of fuels inits operation. The multi-fuel turbine comprises a central exit duct anda reverse flow annular combustor.

Preferred embodiments of the invention are characterized by an overallarrangement where the exit side of the combustor is pointing into adirection essentially opposite to a major flow direction of the exitduct (called reverse flow arrangement).

The invention offers several advantages. The combustion chamber of theinvention is working properly during the critical start phase of the gasturbine. Also during regular operation the system reaches a stable andvery reliable state. The switching from a liquid fuel to a gaseous fuelor vice versa takes place without any noticeable interruption, whichmeans that the response time is very low. The measured combustionchamber efficiency is very high (it was measured to be about 0.98 atmain regime) on maximum load and on partial load. The emissioncharacteristics are excellent as compared to other gas turbines. Inparticular the NOx emissions are quite low on maximum load and onpartial load.

It is another advantage of the invention, that a multi-fuel turbinegenerator set could be powered by various combustibles according to theactual need or taking into consideration the availability of resources(such as LNG, diesel fuel, palm oil or syngas).

Further advantages will become apparent from the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will in thefollowing be described in detail by means of the description and bymaking reference to the drawings.

FIG. 1A shows a cross-section of a multi-fuel turbine, according to thepresent invention;

FIG. 1B shows a magnified cross-section of a part of the multi-fuelturbine of FIG. 1A;

FIG. 1C shows another magnified cross-section of a part of themulti-fuel turbine of FIG. 1A;

FIG. 1D shows rear view of the multi-fuel turbine of FIG. 1A;

FIG. 2A shows a cross-section of an air-blast atomizer, according to thepresent invention;

FIG. 2B shows a cross-section of the diffuser shape of the air-blastatomizer of FIG. 2A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Terms are herein used which also find use in relevant publications andpatents. It is noted however, that the use of these terms shall merelyserve a better comprehension. The inventive idea and the scope of thepatent claims shall not be limited in their interpretation by thespecific selection of the terms. The invention can be transferredwithout further ado to other systems of terminology.

A first embodiment of the invention is now described in connection withthe FIGS. 1A through 1D and FIG. 2.

The invention concerns a multi-fuel turbine 100 which has a reverse flowannular combustor. Reverse flow annular combustor turbines in variousconfigurations are known in the art. In general terms, a reverse flowannular combustor turbine 100 comprises one reverse flow annularcombustor arranged around the periphery of a (central) exit duct 30. Inconnection with FIGS. 1A-1D an embodiment is described which comprisestwelve air blast atomizers 10 in a reverse flow annular combustionchamber 50. The annular combustion chamber 50 is arranged next to aradial inflow turbine 63, as illustrated in FIG. 1A.

As indicated above, the turbine 100 comprises a central exit duct 30which typically has a funnel shape, a cylindrical shape or the shape ofa truncated cone. The exit duct 30 may also comprise various sectionsfor instance with an upstream truncated cone-shaped portion followed bya downstream cylindrical portion, like the exit duct 30 of FIG. 1A. Thearrow EG (EG schematically represents the exhaust gases flow) in FIG. 1Apoints in the downstream direction. The central exit diffuser duct 30 issymmetric with respect to a longitudinal axis LA2.

According to the invention, a reverse flow annular combustor 50 with airblast atomizers 10 is positioned in a annular arrangement around thecentral exit duct 30. The combustor 50 is sitting outside of the exitduct 30. The reverse flow annular combustor 50 is supplied/powered byseveral air-blast atomizers 10.

Details of a preferred embodiment of an air-blast atomizer 10 are shownin FIG. 2A. The air-blast atomizer 10 of FIG. 2A can be employed in allembodiments of the invention.

According to the invention, all embodiments comprise multi-fuelair-blast atomizers 10 which are designed in order to be feedable by aliquid fuel LF and a gaseous fuel GF. The inventive turbine 100comprises multiple (preferrably four and more) multi-fuel air-blastatomizers 10.

All embodiments of a multi-fuel air-blast atomizer 10 of the inventioncomprise a diffuser 11 with an exit side 12 and an inlet side or zone13, as shown in FIG. 2A.

The diffuser 11 has a rotationally symmetric shape with a first largediameter area A1 serving as the inlet zone 13, followed by a second areaA2 with constriction of diameter and a third area A3 with a diameterexpanding towards the exit side 12. The shape of the diffuser 11 of FIG.2A is depicted in FIG. 2B. FIG. 2B shows the shape of a preferreddiffuser 11.

In other words, the diffuser 11 has a rotationally symmetric shape withrespect to a longitudinal axis LA1. The shape is derived from anhourglass shape where an area A2 with constriction separates the inletzone 13 from a funnel shaped area A3, and wherein the funnel shaped areaA3 opens out into the exit side 12.

There is an orifice 14 which is designed for the injection of the liquidfuel LF. The orifice 14 is typically placed at the circumference of thewall enclosing/defining the diffuser 11 of the air-blast vaporizer 10.Preferably, the orifice 14 is oriented in a radial direction withrespect to the central longitudinal axis LA1 of the air-blast atomizer10. Each atomizer 10 further has a gas inlet 15 which is designed forthe injection of the gaseous fuel GF. Preferably, the gas inlet 15 ofall embodiments is co-axially arranged with respect to the longitudinalaxis LA1. In preferred embodiments of the invention, the gas inlet 15enters the diffuser 11 at the back side so that the gaseous fuel GF isstreaming right into the center of the inlet side or zone 13. An airinlet 16 is provided, which is designed for the intake of compressed air(provided by an upstream portion 66 of the turbine 63, cf. FIG. 1A). Theembodiment of FIG. 2A shows an air inlet 16 which takes in air at thecircumference and which redirects the air in a direction which isessentially parallel to the longitudinal axis LA1. At the inlet side orzone 13 the gaseous fuel GF and the compressed air are mixedautomatically. A short distance downstream from the gas inlet 15 theorifice 14 is spraying the liquid fuel LF into the diffuser 11, if bothkinds of fuels GF and LF are used at the same time. The orifice 14 islocated near the second area A2 with constriction of diameter or rightat the second area A2.

For the purposes of the present description and claims, a multi-fuelair-blast atomizer 10 is a device which takes in gaseous fuel GF and/orliquid fuel LF and compressed air, mixes these constituents and releasesthem through the exit side 12 into the combustor 50 so that an efficientcombustion process can be initiated and maintained in the combustor 50.

Generally speaking, the orifice 14, the gas inlet 15, and the air inlet16 of all embodiments are positioned at or close to the inlet side orzone 13 of the air-blast atomizer 10 so as to produce a high-pressuregas stream GS. This high-pressure gas stream GS exits the diffuser 11via the exit side 12, as schematically illustrated in FIG. 2A. Thishigh-pressure gas stream GS typically is a sub-sonic two phase gasstream. The flow of this gas stream GS is subsonic, which means that ishas a Mach number smaller than one, because one has to decrease thevelocities in the combustion chamber. The flow of this gas stream GS istwo-phase because it consists of air and gaseous fuel GF, or air andliquid fuel LF, or air and gaseous fuel GF plus liquid fuel LF, if bothkinds of fuel GF and LF are employed at the same time.

According to the invention, each of the air-blast atomizers 10 istangentially arranged with respect to the reverse flow annular combustor50, as can be seen in FIGS. 1B and 1C. The tangential arrangement isessential since it causes a vortex stream inside the combustor 50 formain stabilization in the primary combustor zone PCZ (in FIGS. 1B and 1Cthe position/dimension of the primary combustor zone PCZ is depictedschematically by means of a simple oval). The primary combustor zone PCZis a region of the reverse flow annular combustor 50 which is locateddownstream of the air-blast atomizer(s) 10. A so-called dilution regionDR follows downstream of the primary combustor zone PCZ (in FIGS. 1B and1C the position/dimension of the dilution region DR is depictedschematically). The vortex is established and maintained by thetangential arrangement of the diffuser 11 which injects the two phasegas stream GS tangentially into the chamber of the combustor 50.

An igniter 53 is preferrably positioned inside the reverse flow annularcombustor 50 so as to be able to ignite the primary combustor zone PCZ.A preferred position of the igniter 53 is indicated in FIG. 1A by meansof the symbol

Practically, the vortex formed by the airblast injector 20 in combustor50 produces or serves as main stabilization stream. The vortex in thecombustor 50 is crucial for a flame stabilization in the combustor'sprimary zone. The stabilization process of the reverse flow annularcombustor 50 is designed so that the vortex is established andmaintained by the special arrangement and orientation of the air-blastatomizers 10.

Preferably, all embodiments of the invention employ a gas inlet 15which, together with the air pressed into the air-blast atomizer 10,form a high-speed subsonic gas stream GS.

FIG. 1D show a rear view where all twelve air-blast atomizers 10 arevisible. This Figure shows that all atomizers 10 have the same radialdistance with respect to the longitudinal axis LA2. One can also see thegas fuel pipes 102 which here comprise a common ring-shaped pipe. Theliquid fuel pipes 101 are hidden behind the gas fuel pipes 102.

It is one problem of a multi-fuel turbine 100, that each type of fuelhas a different fuel mass flow. In order to ensure an identical fuelheat input (which is essential for a stable operation of the multi-fuelturbine 100 or the multi-fuel turbine generator set, respectively), theflow of the gaseous fuel GF has to be stronger when processing flare gasthan in case of syngas serving as gaseous fuel GF, for instance. Theflows of a liquid fuel LF and a gaseous fuel GF have to be adjustedfollowing the same principle so that the effective fuel mass flow ismaintained. The control unit CU of the multi-fuel turbine 100 or themulti-fuel turbine generator set controls the actual state andintervenes, if required.

The invention employs a non-premixed combustion scheme. This means thatneither the compressed air and the gaseous nor the liquid fuel(s) aremixed before they enter the diffuser 11 of the air-blast vaporizer 10.This is of particular advantage regarding the processing of syngas,since the hydrogen contained in the syngas might cause a flashback if itis pre-mixed with (hot) air before it reaches the inlet side or zone 13of the diffuser 11. A non-premixed combustion scheme is alsoadvantageous if for instance liquid hydrogen is employed as liquid fuelLF.

In all preferred embodiments of the invention, the mixing of the gaseousfuel GF (e.g. syngas) and the (hot) air takes place in the inlet side orzone 13 of the diffuser 11. Then further compressed (hot) air is mixedafter the two phase gas stream GS has left the air-blast atomizers 10and before it enters the central exit duct 30. Further compressed (hot)air might be fed in via optional air inlets 52 (cf. FIG. 1C).Preferably, in all embodiments of the invention, more than 50% of theair mass flow is injected through optional air inlets 52 into thecombustion chamber 50.

The multi-fuel turbine 100 may further comprise a compressor housing 61with air slots 62. This compressor housing 61 is located at the upstreamside of the central exit duct 30. Between the compressor housing 61 andthe exit duct 30 there is a compressor diffuser vane 105 which diffusesthe compressed hot air and guides it through air channels 65.1, 65.2into the reverse flow annular combustor 50 (this is done via optionalair inlets 52, one of which is visible in FIG. 1C) and to the air inlets16 of the air-blast atomizers 10. Inside the compressor 60 there is apower transmission shaft 107 (and other rotating parts) which isco-axially arranged with respect to the longitudinal axis LA2. The powertransmission shaft 107 rotates around the longitudinal axis LA2. Theactual turbine 63 sits at the downstream end of the shaft 107. Theradial inflow turbine 63 has a number of curved blades (not visible inthe cross-sections) which are arranged so that exhaust gas, redirectedby outlet ducts 51, interacts with these blades and causes a rotation ofthe turbine 63. The turbine 63 also has a number of curved air blades(not visible in the cross-sections) in an upstream portion 66 of theturbine 63 arranged so that air sucked in via the air slots 62 iscompressed by these air blades.

There is a exit duct pipe connection 64 for mechanically connecting thecompressor 60 to the exit duct 30.

The reverse flow annular combustor 50 is placed around the exit duct 30and the whole arrangement sits outside the exit duct 30 and inside anouter combustor housing 104. The outer combustor housing 104 typicallyhas a annular shape.

In the following sections further details are addressed.

A gas turbine is a type of internal combustion engine. It has at leastone downstream turbine (here the turbine 63) following after acombustion chamber 50.

According to the invention, energy is added to the two phase gas streamsGS which are fed via several air-blast atomizers 10 tangentially intothe reverse flow annular combustion chamber 50. Here (liquid and/orgaseous) fuel mixed with air is ignited and combusted. That is, in thereverse flow annular combustion chamber 50 the two phase gas streams GSprovided by the air-blast atomizers 10 are ignited and combusted so asto produce a high pressure gas stream and the temperature is increaseddue to the internal combustion processes. The (reaction) products of thecombustion is forced via cambered outlet ducts 51 into the radial inflowturbine 63 downstream of the combustor 50. The high velocity of the highpressure, hot exhaust gas flow is directed over the blades of theturbine 63. The turbine 63 spins around the longitudinal axis LA2 anddrives a mechanical output (e.g. the shaft 107). Simply phrased, theenergy imposed upon the turbine 63 is taken from the reduction in thetemperature and pressure of the exhaust gas produced by the reverse flowannular combustion chamber 50. The exhaust gases EG is guided along theblades of the turbine 63 and through the jet pipe 30 into a directionparallel to the longitudinal axis LA2. In FIG. 1A the exhaust gas EG isschematically represented by an arrow which points in the downstreamdirection.

In the most preferred embodiments of the invention, air is acceleratedin either a compressor (e.g. in a centrifugal compressor 60 or in anaxial compressor), before the air is fed into the gas inlets 16 of theair-blast atomizers 10. When guided through the inlets 15, 16 and theorifice 14, the pressure and temperature of the air and other gasflow(s) increase(s). Then the two phase gas streams GS pass from thediffusers 11 into the reverse flow annular combustion chamber 50 wherethe temperature increases further due to the combustion processes andthe specific volume of the gases increases, i.e. the gases are caused toexpand. This increased volume of gases is (re-)directed via the outletduct 51 onto the turbine blades of the turbine 63 or it is expanded andaccelerated by means of nozzles before the inherent kinetic energy isextracted by the turbine 63.

The gas stream inside the reverse flow annular combustion chamber 50 iscaused to form a vortex stream due to the specific arrangement of theair-blast atomizers 10. The vortex stream causes a high level of mixtureof the gas “components” which in turn increases the performance of thecombustion. It is a further advantage of the vortex operation that thewalls of the combustion chamber 50 do not get as hot as they would in aconventional combustion chamber.

Depending on the implementation of the invention, the reverse flowannular combustion chamber 50 can be operated without the need of acooling device since the walls remain relatively cool. The compressedair, which is fed via the channels 65.1, 65.2 to the combustor 50, isstreaming along the walls of the combustion chamber 50 and thus providesfor a cooling effect.

The above described operation is initiated using liquid fuel LF or gasfuel GF. Once started, an operator by manual intervention or the controlunit CU can choose the most favorable fuel and switch over the operationat anytime. The switching can be done by means of control lines 71, 71,as schematically illustrated in FIG. 3. These control lines 71, 71interact with actuators 72, 73 (e.g. valves and/or pumps).

Afterwards, an operator or the control unit CU can for instance selectthe most inexpensive fuel in accordance with seasonal and otherfluctuations or the fuel which causes the least emissions (e.g. reducedNOx emissions).

In preferred embodiments of the invention, a multi-fuel turbinegenerator set is provided which is designed in order to be operated withtwo different types of fuels, namely with a gaseous fuel GF and a liquidfuel LF.

In preferred embodiments of the invention, the multi-fuel turbinegenerator set is designed in order to burn gasoline, kerosene, dieseloil, palm oil, liquefied natural gas, or liquefied hydrogen as liquidfuel LF and syngas (a mixture of H₂ and CO), natural gas, or flare gasas gaseous fuel GF. The syngas could be provided by a waste disposalreactor, for instance. The flare gas could be provided by an oilplatform where so far the flare gas is typically flared.

If a liquid fuel LF is processed together with syngas, the liquid fuelLF is injected through small orifices 14 (one orifice 14 per air-blastatomizer 10), into the inlet side or zone 13 (into area A1 or A2) of therespective air-blast atomizer 10. The injected liquid fuel LF is mergedwith a subsonic gas stream GS comprising syngas and compressed air. Thissubsonic gas stream GS is then injected tangentially into the reverseflow annular combustion chamber 50.

There might be an electric cabinet or control cabinet (not shown) whichcomprises switches, high-power semiconductor elements, fuses and thelike. The control unit CU (see FIG. 1A) might be part of the cabinet orit could be realized as separate unit or building block of themulti-fuel turbine 100.

As mentioned before, there is a gas fuel supply 40 and a liquid fuelsupply 41 both of which are in fluid connection with the reverse flowannular combustion chamber 50. The gas fuel supply 40 and the liquidfuel supply 41 are switchable by the control unit CU in order to enablethe multi-fuel turbine 100 to be operated by gaseous fuel GF and/or byliquid fuel LF. FIG. 1A indicates in a schematic block diagram thatthere are control lines 70, 71 which enable the control unit CU toswitch the flow of the gaseous fuel GF and the flow of the liquid fuelLF. Actuators or valves 72, 73 are employed in order to control the flowof the gaseous fuel GF and the flow of the liquid fuel LF.

While the present invention has been illustrated and described withrespect to a particular embodiment thereof, it should be appreciated bythose of ordinary skill in the art that various modifications to thisinvention may be made without departing from the spirit and scope of thepresent.

What is claimed is:
 1. A reverse flow annular combustor for use in aturbine, said combustor comprising at least one air-blast atomizeroperating on a combustible, wherein the air-blast atomizer is a multiplefuel atomizer which has a gas inlet for feeding gaseous fuel as firstcombustible into an inlet zone of the atomizer, an air inlet for feedingcompressed air into the inlet zone, an orifice for injecting a liquidfuel as second combustible into the inlet zone or into an area close tothe inlet zone, and a diffuser for emitting a gas stream at an exit sidecomprising said gaseous fuel, compressed air and said liquid fuel, saidatomizer being arranged with respect to a combustion chamber of saidcombustor so that the exit side of said diffuser points in a tangentialdirection relative to said combustion chamber, and wherein saidcombustor comprises an outlet duct for discharging an exhaust gasproduced by a combustion process of said gas stream inside saidcombustion chamber.
 2. The combustor according to claim 1, wherein saiddiffuser has a rotationally symmetric shape with a first large diameterarea serving as the inlet zone, followed by a second area withconstriction of diameter and a third area with a diameter expandingtowards the exit side.
 3. The combustor according to claim 1, whereinsaid diffuser has a rotationally symmetric shape with an hourglass shapewhere an area with constriction separates the inlet zone from a funnelshaped area, and wherein the funnel shaped area opens out into the exitside.
 4. The combustor according to claim 2, wherein said orifice ispositioned at or close to said constriction.
 5. The combustor accordingto claim 1, wherein said gas inlet is co-axially arranged with respectto a longitudinal axis of said atomizer.
 6. The combustor according toclaim 1, wherein said gas inlet and said air inlet are arranged so thatgaseous fuel and said compressed air are clashing in the inlet zone. 7.The combustor according to claim 1, wherein said atomizer is arrangedwith respect to the combustion chamber of said combustor so that saidgas stream is tangentially discharged via the exit side of said diffuserinto said combustion chamber where a vortex is established.
 8. Thecombustor according to claim 1, wherein said combustor comprising aplurality of atomizers, these atomizers being arranged on a commoncircle.
 9. A multi-fuel turbine comprising a central exit duct pipe anda reverse flow annular combustor in accordance with claim 1, saidcombustors being arranged at the outside of said exit duct pipe so thatthe exhaust gas discharged by the reverse flow annular combustor isstreaming into a direction essentially opposite to a major flowdirection of said exit duct pipe.
 10. The multi-fuel turbine accordingto claim 9, which comprises a turbine which is co-axially arranged withrespect to a longitudinal axis of said exit duct pipe and which furthercomprises a cambered outlet duct connected to said combustor forredirecting said exhaust gas onto blades of said turbine.
 11. Themulti-fuel turbine according to claim 10, wherein said turbine comprisesan upstream portion with air blades for taking in air and for releasingcompressed air.
 12. The multi-fuel turbine according to claim 11,comprising air channels arranged so that compressed air released by saidupstream portion is guided towards air inlets of said atomizers.
 13. Themulti-fuel turbine according to claim 9, wherein said reverse flowannular combustor comprises at least one air inlet arranged so as toprovide a direct air entry into the combustion chamber of saidcombustor.
 14. The multi-fuel turbine according to claim 9, comprising acontrol unit connectable to actuators or valves so as to enable themulti-fuel turbine to be fed by said gaseous fuel and/or by said liquidfuel.
 15. The multi-fuel turbine according to claim 14, furthercomprising liquid fuel pipes and gas fuel pipes for feeding said liquidfuel to said orifices of each vaporizer and said gaseous fuel to saidgas inlets of each vaporizer.
 16. The multi-fuel turbine according toclaim 14, comprising a common ring-shaped liquid fuel pipe and a commonring-shaped gas fuel pipe for feeding said liquid fuel to said orificesof each atomizer and said gaseous fuel to said gas inlets of eachatomizer.
 17. The multi-fuel turbine according to claim 9, furthercomprising an igniter arranged inside the combustion chamber forigniting and maintaining a combustion of the gas stream in saidcombustor.
 18. A multi-fuel turbine according to claim 17, comprising agas fuel supply and a liquid fuel supply in fluid connection with thereverse flow annular combustor, said gas fuel supply and said liquidfuel supply being switchable by a control unit in order to enable saidmulti-fuel turbine to be operated by said gaseous fuel and/or by saidliquid fuel.
 19. A method of combustion within a reverse flow annularcombustor of a gas turbine, comprising the steps: injecting a liquidfuel into an air-blast atomizer and/or injecting a gaseous fuel into aninlet zone of said air-blast atomizer, feeding compressed air into saidinlet zone of said air-blast atomizer, so that said fuels and saidcompressed air are mixed inside said air-blast atomizer and that a gasstream leaves said air-blast atomizer via an exit side and enters acombustion chamber of said reverse flow annular combustor, said exitside of said air-blast atomizer pointing in a tangential directionrelative to said reverse flow annular combustor to create a main vortexflow in said combustion chamber, combusting said gas stream in a primarycombustor zone of said combustion chamber, discharging an exhaust gasproduced by said combusting in said combustion chamber onto blades of aturbine.
 20. The method of claim 19, comprising the following step:switching from a first mode of operation where said air-blast atomizeris fed with said liquid fuel and compressed air into a second mode ofoperation where said air-blast atomizer is fed with said gaseous fueland compressed air; or switching from a second mode of operation wheresaid air-blast atomizer is fed with said gaseous fuel and compressed airinto a first mode of operation where said air-blast atomizer is fed withsaid liquid fuel and compressed air.
 21. The method of claim 20, whereinsaid liquid fuel is selected from the group consisting of gasoline,kerosene, diesel oil, palm oil, liquefied natural gas, liquefiedhydrogen.
 22. The method of claim 20, wherein said gaseous fuel isselected from the group consisting of syngas, natural gas, flare gas.